In a turning machine tool represented by a lathe and a cylindrical grinding machine, a headstock and a tailstock are arranged so as to face each other. The turning machine tool is configured to support a turning object, work between the headstock and the tailstock.
In the tailstock, a shaft hole is passed through a main body along a front-rear direction. A tailstock spindle is fitted in the shaft hole to be movable back and forth. The tailstock spindle is directed its front end to the headstock, and arranged concentrically with a main spindle of the headstock. A center is concentrically attachable to the front end of the tailstock spindle. The tailstock spindle is non-rotatable relative to the main body.
In a center-rotation type tailstock, a center hole is formed in the tailstock spindle. A rotary shaft is supported in the center hole by bearings. The rotary shaft is rotatable and non-movable back and forth relative to the tailstock spindle. A center is concentrically attachable to a front end of the rotary shaft. A dead center attached to the rotary shaft rotates along with the turning object during rotation together with the rotary shaft. The dead center is used as if it were a live center.